Exhaust assembly
A system includes a combustion engine for a genset. The engine having an exhaust to emit water and exhaust gases from the exhaust and a sound-dampening device coupled between the exhaust and a muffler, the sound-dampening device including a tubular member having internal rings.
This invention relates to the field of exhaust assemblies, and more specifically to exhaust assemblies for marine engine applications.
BACKGROUNDIn marine exhaust systems, a flexible exhaust hose is coupled between the combustion engine of a generator set (genset) and a muffler and water separator. These flexible exhaust hoses transfer the exhaust gases and the raw water from the genset to the boat muffler and water separator that are located remote from the genset. Unlike automotive exhaust system that are made of metal, which is a good noise barrier, marine exhaust hoses have to be flexible and thus are not good barriers for noise. Lately, genset noise has been reduced through better designs, thus making the radiated noise from the exhaust hose the major source of overall noise.
One technique to reduce the noise of exhaust hoses is to insulate the exhaust hose with a barrier type material. However, this is not a practical solution since the boat builder supplies the exhaust hose and the builders are typically reluctant to invest the additional time and money to insulate the exhaust hose. What is needed is a more practical technique to reduce marine exhaust hose noise.
SUMMARYA system includes a combustion engine having an exhaust to emit water and exhaust gases from the exhaust and a sound-dampening device coupled between the exhaust and a muffler. The sound-dampening device includes a tubular member having two or more internal rings.
In one option, the tubular member includes a flexible exhaust hose for coupling between the exhaust and the muffler, the flexible exhaust hose having an inner diameter, and the two or more rings are located on the inner diameter of the flexible exhaust hose, each ring having an outer diameter the same as the inner diameter of the flexible exhaust hose and an inner diameter smaller than the inner diameter of the flexible exhaust hose.
In one option, the tubular member includes a rigid tube having a first end connectable to the exhaust and a second end couplable to a flexible exhaust hose. The tube includes an inner diameter, the inner diameter having the at least two rings mounted thereto, each ring having an outer diameter the same as the inner diameter of the tube and an inner diameter smaller than the inner diameter of the tube.
BRIEF DESCRIPTION OF THE DRAWINGS
The following detailed description and accompanying drawings show various embodiments according to the inventive subject matter disclosed herein. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention. Other embodiments may be utilized and structural changes may be made without departing from the scope of the present invention.
In one example, exhaust tube 100 is a two-inch diameter and five-inch long rigid metal pipe, such as a stainless steel tube. Rings 134, 140 can also be formed of stainless steel. The specific diameter and length of the rings 130, 140 and tube 100 can vary. The rings 130, 240 can be welded to the tube body 121.
Exhaust tube 100 reduces radiated noise from exhaust hose 30. Rings 130 and 140 provide a constriction as the water and exhaust gases leave the combustion engine of genset 10. The rings help form the water into water droplets and mix the gas with the water so as to reduce noise generated by the combustion engines. The constriction provided by rings 130, 140 also increases the velocity of the exhaust gas to more effectively pick up drops of water from the bottom of the tube 100 and hose 30 and to be able to carry the water with the gas. Moreover, these water droplets can help absorb sound. Also, the droplets help cool the exhaust gas. Cooler gases have shorter sound waves which are easier to attenuate. Moreover, the rings themselves restrict the sound-dampening device which increases attenuation. These factors, among others, provide for the sound dampening properties provided by exhaust tube 100.
Again, the exhaust assembly of
As shown in
Exhaust hose 200 that can be used by a boat builder instead of the industry standard exhaust hose to reduce the exhaust noise radiated from the hose. As can be seen in
The radiated exhaust noise from the industry standard flexible exhaust hose is predominant in the frequency range of 1 kHz and above. Comparing the frequency spectrums of the different configurations, it can be seen that the radiated exhaust noise from the flexible exhaust hose in the frequency region of 1 kHz and above is significantly reduced when the standard flexible exhaust hose is wrapped or when the flexible exhaust hose with rings is installed or when the exhaust tube with rings is installed. This reduction would be even more dramatic if the frequency spectrum of only the exhaust side of the genset were compared instead of the average of four sides as shown here. The reduction would also be more dramatic if the frequency spectrum was linear not A-weighted as shown. The A-weighting reduces the noise contribution of frequencies above 2 kHz. A linear frequency scale better represents the noise quality improvement due to installing the modified exhaust hose and the modified exhaust tube.
In further embodiments, the exhaust components discussed herein can be used on any marine combustion engine to reduce the radiated exhaust noise from a flexible marine exhaust hose.
The above description is intended to be illustrative, and not restrictive. Many other embodiments will be apparent to those of skill in the art upon reviewing the above description. The scope of the invention should, therefore, be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.
Claims
1. A system comprising:
- a combustion engine having an exhaust to emit water and exhaust gases from the exhaust; and
- a sound-dampening device coupled between the exhaust and a muffler, the sound-dampening device including a tubular member having two or more internal rings.
2. The system of claim 1, wherein the engine is within a genset.
3. The system of claim 1, wherein the tubular member includes a flexible exhaust hose for connecting between the exhaust and a muffler, the flexible exhaust hose having an inner diameter, and the two or more rings are located on the inner diameter of the flexible exhaust hose, each ring having an outer diameter the same as the inner diameter of the flexible exhaust hose and an inner diameter smaller than the inner diameter of the flexible exhaust hose.
4. The system of claim 1, wherein the tubular member includes an exhaust tube having a first end connectable to the exhaust, the tube including an inner diameter, the inner diameter having the at least two rings mounted thereto, each ring having an outer diameter the same as the inner diameter of the tube and an inner diameter smaller than the inner diameter of the pipe.
5. The system of claim 1, wherein the system is adapted for marine use.
6. An apparatus comprising:
- a flexible exhaust hose for connecting between a combustion engine and a muffler, the flexible exhaust hose having an inner diameter; and
- two or more rings located on the inner diameter of the flexible exhaust hose, each ring having an outer diameter the same as the inner diameter of the flexible exhaust hose and an inner diameter smaller than the inner diameter of the flexible exhaust hose.
7. The apparatus of claim 6, wherein the two or more rings are spaced about 4½ inches apart from each other along a length of the flexible exhaust hose.
8. The apparatus of claim 6, wherein the flexible exhaust hose has an outer diameter of about 2 inches.
9. The apparatus of claim 6, wherein the flexible exhaust hose is adapted for marine conditions.
10. The apparatus of claim 6, wherein the length of the flexible exhaust hose is about 6 feet or less.
11. An apparatus comprising:
- a rigid tube having a first end connectable to an exhaust outlet of a combustion engine, the tube including an inner diameter, the inner diameter having at least two rings mounted thereto, each ring having an outer diameter the same as the inner diameter of the tube and an inner diameter smaller than the inner diameter of the pipe.
12. The apparatus of claim 11, wherein the tube is a rigid metal pipe.
13. The apparatus of claim 11, wherein a second end of the tube is connectable to a flexible marine exhaust hose.
14. The apparatus of claim 11, wherein the tube includes a first ring mounted to the first end of the tube and a second ring mounted to a second end of the pipe.
15. The apparatus of claim 11, wherein the tube and the rings are stainless steel.
16. The apparatus of claim 11, wherein the rings are adapted to create water droplets as exhaust gases and cooling water exit the genset.
Type: Application
Filed: Jan 27, 2004
Publication Date: Jul 28, 2005
Patent Grant number: 7721537
Inventors: Deborah Klinkert (Plymouth, MN), Douglas Hanson (Blaine, MN)
Application Number: 10/765,708